code: def extract_labels(pdbbind_label_file):
      """Extract labels from pdbbind label file."""
      assert os.path.isfile(pdbbind_label_file)
      labels = {}
      with open(pdbbind_label_file) as f:
          content = f.readlines()
          for line in content:
              if line[0] == "#":
                  continue
              line = line.split()
              # lines in the label file have format
              # PDB-code Resolution Release-Year -logKd Kd reference ligand-name
              # print line[0], line[3]
              labels[line[0]] = line[3]
      return labels
  
file_path: deepchem/datasets/construct_pdbbind_df.py
imports: from __future__ import print_function
  import pickle
  import os
  import pandas
  from rdkit import Chem
  from glob import glob
  import re
  from sklearn.externals import joblib
label_desc: Use image node_id 1 for calling a global function with example usage: extract_labels(pdbbind_label_file) and returns: labels